As computer technology develops, the speed of processors also increases. Many modern processors utilize a parallel FLASH memory, which has a relatively high operating speed but requires many pins for the necessary connections, thereby increasing the cost of the processing unit design. Serial FLASH needs very few pins to transmit the data in some kind of serial form, but with a lower bandwidth compared to that of a parallel FLASH. Conventional processors download the whole firmware from the serial flash to a DRAM before the system starts up. However, large firmware will require a large DRAM space. Lowering the cost and complexity of the processing unit while maintaining a fast operational speed therefore becomes an important issue for the manufacturers.